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The entry to a holding pattern is often the hardest part for a novice pilot to grasp, and determining and executing the proper entry while simultaneously controlling the aircraft, navigating and communicating with ATC requires practice. There are three standard types of entries: direct, parallel, and offset (teardrop). The proper entry procedure is determined by the angle difference between the direction the aircraft flies to arrive at the beacon and the direction of the inbound leg of the holding pattern.''Instrument Flying Handbook'' (FAA-H-8083-15A), Standard Entry Procedures, page 10-12.
* A ''direct'' entry is performed just as its name would suggest: the aircraft flies directly to the holding fix, and immediately begins the first turn outbound.
* In a ''parallel'' entry, the aircraft flies to the holding fix, parallels the inbound course for one minute outbound, and then turns back, re-intercepting the inbound track, and continues in the hold from there.
* In an ''offset'' or ''teardrop'' entry, the aircraft flies to the holding fix, turns into the protected area, flies for one minute, and then turns back inbound, proceeding to the fix and continuing from there.
File:HoldDirectEntry.svg, Direct entry (Sector 3)
File:HoldParallelEntry.svg, Parallel entry (Sector 1)
File:HoldTeardropEntry.svg, Teardrop entry (Sector 2)
The parallel and teardrop entry are mirrored in case of a left-hand holding pattern.
Aircraft Operations
', Volume I Flight Procedures, Part I — Section 6, Chapter 1. * Up to : * : * : * Above : M0.83 With their higher performance characteristics, military aircraft have higher holding speed limits.
E6BX Holding Entry Calculator and Trainer
* ttps://flightcrewguide.com/wiki/inflight/entry-holding/ Flight Crew Guide - Entry into the Holdingbr>Flight Crew Guide - Flying the Holding pattern – Wind correction
SKYbrary - Holding Pattern
{{Flight phases Flight phases Air traffic control
aviation
Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air ...
, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace.
Implementation
A holding pattern forinstrument flight rules
In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
The U.S. Federal Aviation Administration's (FAA) ''Instrument Fly ...
(IFR) aircraft is usually a racetrack pattern based on a ''holding fix''. This ''fix'' can be a radio beacon such as a non-directional beacon
A non-directional beacon (NDB) or non-directional radio beacon is a radio beacon which does not include directional information. Radio beacons are radio transmitters at a known location, used as an aviation or marine navigational aid. NDB are ...
(NDB) or VHF omnidirectional range
Very high frequency omnirange station (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network ...
(VOR). The fix is the start of the first turn of the racetrack pattern. Aircraft will fly towards the fix, and once there will enter a predefined racetrack pattern. A standard holding pattern uses right-hand turns and takes approximately 4 minutes to complete (one minute for each 180-degree turn, and two one-minute straight ahead sections). Deviations from this pattern can happen if long delays are expected; longer legs (usually two or three minutes) may be used, or aircraft with distance measuring equipment
In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 9 ...
(DME) may be assigned patterns with legs defined in nautical mile
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Historically, it was defined as the meridian arc length corresponding to one minute ( of a degree) of latitude. Today ...
s rather than minutes.
Usage
The primary use of a holding is delaying aircraft that have arrived at their destination but cannot land yet because of traffic congestion, poor weather, or runway unavailability (for instance, duringsnow removal
Snow removal or snow clearing is the job of removing snow after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions.
De-icing and anti-icing
De-icing is defined as removal ...
or emergencies). Several aircraft may fly the same holding pattern at the same time, separated vertically by or more. This is generally described as a ''stack'' or ''holding stack''. As a rule, new arrivals will be added at the top. The aircraft at the bottom of the stack will be taken out and allowed to make an approach first, after which all aircraft in the stack move down one level, and so on. Air traffic control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
(ATC) will control the whole process, in some cases using a dedicated controller (called a ''stack controller'') for each individual pattern.
One airport may have several holding patterns; depending on where aircraft arrive from or which runway is in use, or because of vertical airspace limitations.
Since an aircraft with an emergency has priority over all other air traffic, it will always be allowed to bypass the holding pattern and go directly to the airport (if possible). This causes more delays for other aircraft already in the stack.
Entry procedures
The entry to a holding pattern is often the hardest part for a novice pilot to grasp, and determining and executing the proper entry while simultaneously controlling the aircraft, navigating and communicating with ATC requires practice. There are three standard types of entries: direct, parallel, and offset (teardrop). The proper entry procedure is determined by the angle difference between the direction the aircraft flies to arrive at the beacon and the direction of the inbound leg of the holding pattern.''Instrument Flying Handbook'' (FAA-H-8083-15A), Standard Entry Procedures, page 10-12.
* A ''direct'' entry is performed just as its name would suggest: the aircraft flies directly to the holding fix, and immediately begins the first turn outbound.
* In a ''parallel'' entry, the aircraft flies to the holding fix, parallels the inbound course for one minute outbound, and then turns back, re-intercepting the inbound track, and continues in the hold from there.
* In an ''offset'' or ''teardrop'' entry, the aircraft flies to the holding fix, turns into the protected area, flies for one minute, and then turns back inbound, proceeding to the fix and continuing from there.
Speed limits
Maximum holding speeds are established to keep aircraft within the protected holding area during their one-minute (one-minute and a half above MSL) inbound and outbound legs. Forcivil aircraft
Civil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most of the countries in the world are members of the International Civil Aviation Organization and work ...
(not military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
) in the United States and Canada, these airspeeds are:
* Up to MSL: 200 KIAS
* From MSL: 230 KIAS
* MSL and above: 265 KIAS
The ICAO Maximum holding speeds:ICAO Doc 8168 Vol. I, Aircraft Operations
', Volume I Flight Procedures, Part I — Section 6, Chapter 1. * Up to : * : * : * Above : M0.83 With their higher performance characteristics, military aircraft have higher holding speed limits.
See also
*Heathrow arrival stacks
Inbound aircraft to London Heathrow Airport typically follow one of a number of Standard Arrival Routes (STARs). The STARs each terminate at one of four different RNAV waypoints (co-located with VOR navigational aids), and these also define fou ...
* Flight planning
Flight planning is the process of producing a flight plan to describe a proposed aircraft flight. It involves two safety-critical aspects: fuel calculation, to ensure that the aircraft can safely reach the destination, and compliance with air t ...
* Loiter
Loitering is the act of remaining in a particular public place for a prolonged amount of time without any apparent purpose.
While the laws regarding loitering have been challenged and changed over time, loitering is still illegal in various j ...
References
*Aeronautical Information Manual (AIM) paragraph 5-3-8 https://www.faa.gov/air_traffic/publications/atpubs/aim_html/ *(7) "A Treatise on the Holding Pattern: Expelling the Myths and Misconceptions of Timing and Wind Correction:, L. Glatt, PhD. ATP, CFI-AI, (2016), https://www.holdingpattern.com/holding-patterns.html *(8) "Holding Patterns 101: Finding the Holy Grail of Timing and Wind Correction", L. Glatt, PhD., ATP, CFI-AI (2018), https://www.holdingpattern.com/holding-patterns.htmlExternal links
E6BX Holding Entry Calculator and Trainer
* ttps://flightcrewguide.com/wiki/inflight/entry-holding/ Flight Crew Guide - Entry into the Holdingbr>Flight Crew Guide - Flying the Holding pattern – Wind correction
SKYbrary - Holding Pattern
{{Flight phases Flight phases Air traffic control